Automatic mercury switch fuse



June 30, 1953 l. SHAMAH 2,644,054

AUTOMATIC MERCURY SWITCH FUSE Filed July 1, 1950 2 Sheets-Sheet 1 fk/i w ATTORNEY June 30, 1953 1. SHAMAH 2,644,054

AUTOMATIC MERCURY SWITCH FUSE Filed July 1, 1950 2 Sheets-Sheet 2 INVENTOR. ISRAEL SHAMAH 3JJM AT TOR NEY Patented June 30, 1953 UNITED OFFICE 2,644,052 AUTOMATIC MERCURY SWITCH FUSE Israel Shamah, New York, N..Y., assignor to Ismah Corporation of New York Application July 1, 1950, Serial No. 171,631

6 Claims.

This invention relates to an automaticmercury switch fuse.

It is an object of the present invention to provide an automatic switch fuse which is operable as a switch tomake and break an electric circuit and which, upon utilizing the explosive properties of the mercury, will break the electric circuit upon overload and thereby serve as a fuse and wherein the mercury will be displaced to a station removed from the contacts on the overload taking place so that to'reestablish the circuit, the operating arm will need to be adjusted.

It is another object of the present invention to provide an automatic switch fuse wherein the capsule for the mercury is adjustable and requires its movement to three positions, the intermediate position is established after having moved the operating member to one position to set the mercury globule, automatically by a single spring member having portions adapted to enter detent openings of the operating member or if the operating member is differently formed having detent openings to receive such member and to retain the operating member in the intermediate set or off position.

Other objects of the present invention are to provide an automatic mercury switch fuse of the above type which is of simple construction, inexpensive to manufacture, easy to assemble, easy to install in the wall openingwith no more effort than with the standard switches, to reduce the expense of wiring a household and to provide a fuse with each switch and in each switch circuit and thereby to eliminate the need for fuse re- Fig. 3 is an elevational view similar to Fig. 2,v

but with portions of the switch broken away and the operating member moved to an off position to break the electric circuit.

Fig. 4 is an enlarged fragmentary vertical sectional view taken on line 44 of Fig. 2.

Fig. 5 is a fragmentary sectional view taken generally on line 5-5 of Fig. 2.

Fig. 6 is a perspective and. collective view of the V 2 parts of a switch fuse constructed according to a modified form of the invention.

Fig. '7 is a front elevational view of the switch fuse shown in Fig. 6, the parts thereof being assembled.

Fig. 8 is a. vertical sectional view taken on line 8-3 of Fig. 7.

Fig.9 is a collective and perspective view of the parts of a still further form of the invention.

Fig. 10 is a side elevational view of the switch fuse of Fig. 9 with the operating lever in the set position.

Fig.11 is a side elevational view of the switch shown in Figs. 9 and 10 with the operating lever in the off position and with portions of the supporting casing broken away.

Fig. 12 is an enlarged sectional View line l2-l2 ofFigvlo.

Fig. 13 is a fragmentary sectional and perspective view taken generally on line l3|3 of Fig. 10.

Fig. '14 is a fragmentary view taken through the supporting body andshowing one of the con tact terminals fitted in the bottom slot thereof.

Referring now particularly to the form of the invention shown in Figs. '1 to 5, [5 represents a casing of insulating material which is transparent and which has one end open,as indicated at [6, to receive the various switch fuse parts in a manner to 'be presently described. In the bottom of the opening 16, there is secured a leaf spring I! as by means of a rivet l8 and which is turned up to provide an engaging head Iii. This engaging head enters either notch 20 or 2| to retain operating member 22 in either the set position, as shown in Fig. 2, ,or in the off position, asshown in Fig. 3.

The operating member 22 is formed of two parts 22 and 22" preferably of insulating material and has a handle portion 23 that projects outwardly from the opening 16 of the insulated casing 15. V

On the upper edge of the operating member 22 isan elongated non-conductive tubular memher or tube 24 formed of insulating material,

taken on formed also of two parts and adapted to contain a globule 25 of mercury. This tube is closed at its ends and is longitudinally and downwardly curved. The upper edge of the operating member 22 is curved to conform to the curved shape of the tube 26. The parts of the tubular member 24 maybe respectively integral with the respective parts 22' and 22". of theoperating member 22, as shown clearly in Fig. 4.

In one end of the downwardly curved tubular member are opposing electrical contacts or contact terminals 26 and 2'! adapted to be bridged by the globule of mercury in order to establish a circuit. Lead wires 26' and 2'! respectively extend to contact washers 28 and 29 from the terminals 26 and 21. The washer 28 is held in place by a flanged internally threaded pinion member 30 while a similar member 31 supports the contact washer 29. These sleeve members 30 and 3| are slidable into and extend between grooves 32 and 33 in the respective wall faces of the opening l6 of the casing i5, the inner ends of the grooves 32 and 33 extending downwardly and having respectively wall holes 34 and 35. Screws 3B and 31 respectively extend into the sleeves 30, to retain the operating member in the casing l5 so that it may be tilted within the casing. Cable wires 39 and 40 are secured to the unit respectively by these screws 36 and 31.

The switch fuse can be mounted directly upon a support by flanges 4! and 42 and by fastening elements extending respectively through the openings thereof. With flanges 43 and 44 on the open end of the casing, the unit can be secured to a receptacle bracket plate 45, common with the brackets used today with the standard wall switches. The bracket 45 has hole 45 for receiving respectively screws 48 and 49 which are made secure respectively by nuts 50 and 5| lying respectively against the rear faces of the respective flanges 43 and 44. Through this bracket 45 and openings 53 therein, the unit can be fitted into and supported to the wall receptacle, the attaching screws passing through the openings 53 and into the wall receptacle casing.

In operation, the lever 22 is manipulated to adjust the mercury globule 25 in the downwardly curved closed tube 24. By moving the operating member 22 downwardly to the position shown in Fig. 3, the mercury globule is shifted to the left end of the non-conductive tube and free of the contact terminals 26 and 21 whereby to break the circuit. When it is desired to set the switch and close the circuit, the operating lever is brought first up to a dotted line position, as indicated at 54 in Fig. 2, so that the mercury globule is shifted to the contact end of the tube 24 and over the hump in the upper edge of the operating member 22. Upon releasing the operating member, the spring I! through its centering head portion I9 will bring the operating member to the position shown in full lines in Fig. 2 and with the head portion I9 lying in the notch 20 on the rear of the operating member 22. The head 19 of the spring I! will enter the notch 2| of the operating member to hold the operating member in the off position, as shown in Fig. 3.

It is well known that mercury will explode under overload conditions and in doing so a circuit established between the contacts 26 and 2'! can be permanently broken. It is found that the mercury will move sufliciently through the tube and over the hump so as to lie in the end removed from the terminals upon this overload taking place. Accordingly, the arrangement is such as to provide a fuse in a simple manner in a switch of the mercury type. The inherent characteristics of mercury makes possible the utilization of this switch as a fuse. Additional safeguard is given to the household as a fuse is provided with every switch circuit in the room and over the entire house.

Referring now particularly to Figs. 6, 7 and 8, there is shown another form of the invention 4 which comprises generally a main molded casing body of insulating material 60, an operating member 61 with a mercury tube 62 of insulating material and an operating leaf spring 63 and a retaining ring 64 which couples the parts together when fastened by screws 55 and -66 to the casing body 60.

The casing body 50 has radially inwardly extending bosses 6'1 and 68 with threaded openings 61' and 68' respectively for receiving the screws 65 and 66 that pass through the retaining ring 64. In order to secure the casing body 60 to a wall surface, there are provided other bosses 69 and 10 having respectively openings 69 and H3 through which fastening screws H and 12 respectively extend, Fig. 8. Extending upwardly from the bottom of the casing body is a sleeve projection 13 for receiving an inwardly extending projection 14 of the operating member 6!. This projection 13 provides a journal bearing on which the operating member 6| can rotate. Terminal plates 15 and T6 are provided on the bottom of the casing body 60 to which wires 11 and 18, leading from the downwardly curved mercury tube '52, may be connected.

In the projection M of the operating member BI is a longitudinally extending slit 19 into which is fitted the end of the leaf spring 63. The leaf spring 63 has a bent head portion adapted to seat in either of notches 8| or 82 whereby to hold the operating member 51 in the proper positions. The operating member has a turn knob 33, Fig. '7, by which it is turned and the retaining ring 64 has indications thereon telling the direction in which to move the operating member 3|. The mercury globule in the tube 62 on the operating member is transferred from one end of the tube to the other by turning the operating member 5i. To turn on the switch to establish a circuit, the knob 83 is turned to the on position, as shown in Fig. 7, and upon release of the knob spring 63 through its head portion 60 will locate the operating member and the tube 62 in the set position. On turning the knob 83 toward the off position, the head portion 80 of the spring 63 will enter the other notch to hold the operating member in that position. The mercury tube 62 is held in place by a strap bracket 84 and is so positioned that when in the set position any movement of the globule resulting from an overload on the circuit and an explosion of the mercury, will cause the globule of mercury to be retained in the end free of the contacts in the tube. To reestablish this circuit, the operating member must again be moved to the on position and released. Holes 35 and 88 are provided in the retaining ring 64 for receiving the respective screws 65 and 66.

Referring now particularly to Figs. 9 to 14, there is shown a still further form of the invention. According to this form of the invention, 53 represents a casing body formed preferably of molded plastic insulating material and having an open end 9| and side slots 92 and 33 in the side walls thereof. Said side slots are adjacent bottom 94 and serve to receive respectively contact terminals and 96. These contact terminals have respectively depressions 95' and '96 serving to receive rounded trunnion contacts '91 and 98. These trunnion contacts are mounted on a hollow operating member 99 formed of two parts preferably of insulating material and providing a downwardly curved tubular portion Hill of insulating material adapted to contain a mercury globule IilI. The roundedsxtrunnion contacts 91 and 98 respectivelylhaveelectrical contacts I02 and IE3 extending into the tubular portion Ice. The contact terminal's'95and 96 havetheir outwardly pressed portions 95' and 96' seated in small pockets on'the inner faces of the walls of the casing body 98, as indicated respectively at I94, Fig. 14, whereby to prevent the outward shifting of the contact terminals 95 and 95 from their respective slots in the cas ing body. l The operating member 99 has a handle portion 5&5 and a top channel formation I'OB in which head portion I01 of leaf spring IUS may ride as the operating member- 995s tilted. The spring head portion" I01 has two pockets Illa-and ISO in which a pointed endIII of the operating member 99 may extend to hold the'operating member in its adjusted position. When theoperating member 99 is moved 'tothe on'position, as indicated in dotted lines at I I2 in- Fig. '10, the mercury globule IElI is transferred to the contact end of the curved tubular-portion 1 oil. The head portion of the spring I08 will be-expanded, as indicated in dotted lines in Fig. 10, and upon the operating member being released the spring-will through the entrance of portion Ill of the operating member into pocket iii! of the spring head portion It? cause the operating member to assume the full line position shown in Fig. 10. If the operating member '99 is tilteddown to the 01f position, as shown in Fig-.- 11, the pointed end portion lIi of the operating -member 99 will become seated in the pocket I09 -ofthe spring I08. The spring N38 has a folded forward end H3 adapted to enter recess I M in the forward end of the casing body 98. Through this means, the spring His is supported in the casing body 90.

A mounting plate i I5 has inwardly struck projections H5 and ill adapted to engage respectively with bosses I 58 on the top and bottom portions of the casing body 90. Tabs H9 and I can be secured respectively over bosses I2I.

Each of the contact terminals 95 and 98 serve as a support for the insulated operating member 99. Each terminal has a top portion I22 adapted to lie against the inner wall face of the casing part above the upper edge of the opening 92 and two outwardly struck and bent portions I23 and I24, one of which is adapted to be extended over the outer face of the side wall beyond the end of the slot.

It should be apparent that with the form of the invention just described that there is a difference over the first form of the invention in that the notches are provided in the spring itself rather than in the operating member and that the spring is differently connected to the casing part.

It should be apparent that with the last discussed form that the number of parts required to form the unit has been kept to a minimum and free as much as possible of screw connections.

It should also be apparent that with the form of the invention shown in Fig. 9 that the assembly of the same can be effected in a quick manner.

It should also be apparent that there has also been provided a combined switch and fuse which is of simple construction and inexpensive to manufacture.

While various changes may be made in the detail construction, it shall be understood that such changes shall be within the spirit and scope of the present invention as defined by the appended claims.

6 .iWhat'is claimed is: 3 j

1. A combined mercury switch iandfuse come prising a casing body part, a downwardly, curved elongated tubular non-conductive'm'ember closed at its ends and having contact'terminals in one end thereof, a globule of mercury within the tubular member and adapted to abridge the contact terminals, an operating member supporting said tubular member, means for securing the operating memberto the casing part for tilting movement between set and non-set positions whereby the mercury lobule can be shifted in the downwardly curved tubular member from oneend to-the other end thereof to operate as a switch, and means extending between the casing body and the operating member to retain the operating member in its adjusted positions, said mercury globule with the downwardly curved tubular member serving as a fuse between said contact terminals in the set position upon overload of a circuit to be connected thereto, the operating member and the tube being so positioned in the set position of the operatin member to trap the mercury globule at the end of the tube opposite from the contact end when the mercury globule is exploded upon overload. I

2. A combined mercury switch'and fuse comprising a casing part, an operating member pivotally connected to the casing part, andhaving a rounded top edge, a non-conductive downwardly curved tubular member closed at its ends and conforming to the rounded top edge of the operating member, said tubular member having opposed switch contacts therein and a globule of mercury 'shiftable' from'on'e'end' of" the tubular member to the other and over the curve thereof to operate as a. switch in the set position, said operating member serving to shift the mercury globule and adjust it between two positions, spring means extending between the casing part and the operating member to retain the operating member in the set and off positions of the mercury globule, said curved tubular member in the set position permitting the entrapment of the mercury globule in the opposite end from the contacts upon the explosion thereof resulting from an overload of a circuit to be connected thereto, whereby to operate as a fuse.

3. A combined mercury switch and fuse comprising a casing part, an operating member pivotally connected to the casing part, a non-conductive tubular member extending over the curved upper edge of the operating member and closed at its ends, opposed contact terminals in the one end of the tubular member, a mercury globule shiftable in the tubular member, said operating member being operable between non-set and set positions and having adjacent notches therein, a spring anchored to the casing part and having a head portion workable in one of the notches of the operating member to position the operating member in its set position and to retain the same in the adjusted position and engageable with the other notch to hold the operating mem 7 and set positions having a projection a'daptedto enter either of the pocket formationsof the spring whereby to hold the operating member in its adjusted positions, a mercury globule shiftable in the curved tubular member from one endto the other and said operating member in one of its positions being so held as to position the curved tubular member for effecting the entrapment of the mercury globule in the end of the tubular member opposite from the contacts upon the explosion of the globule being effected between the contacts. y Y

5. A combined mercury switch and fusecom prising a casing part, said part being generally of cylindrical shape with an end open and having pocket formations on its inner Wall, an operating member adjustable upon the body part between non-set and set positions and in the open end thereof, a non-conductive tubular member having closed ends and opposed contactterminals in one of the ends secured to the operating member, said tubular member being downwardly curved, a glob ule of mercury shiftable between the ends or the tubular member, a spring connected to the operating member and having a head portion adapted to be worked into the pocket formations on the inner wall of the cylindrical part to position and retain the operating member in its ad justed positions, said operating member having an adjusting knob and a retaining ring connected to the cylinder casing part to prevent the outward displacement of the operating member.

6. A mercury switch fuse comprising a body part having an open end and being hollow, said body part having parallel side walls with side notches therein extending inwardly from the open end of the body part, terminal supports fitted into the wall slots of the body part and having depressions on the inner faces thereof, an operating member having contact trunnions pivotally engaging the depressions on the inner faces of the terminal supports, a downwardly curved elongated non-conductive tubular member provided on the operating member and having contact terminals extending respectively from the contact trunnions, a mercury globule in the tubular member and adapted to bridge the contacts thereof and shiftable from one end to the other end thereof, said operating member having a projection thereon, a leaf spring having a folded portion extending into the front end of the casing body part, said spring having pocket openings therein adapted to receive the projection of the operating member wherein to retain the operating member with the tubular member in the adjusted positions thereof, said operating member holding the tubular portion in one position whereby upon an overload of an electric circuit the mercury may be exploded and entrapped at the opposite end of the tubular portion from the contact terminals.

ISRAEL SHAMAH.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,920,032 Green July 25, 1933 2,110,255 Barnes Mar. 8, 1938 

